Annular sliding valve for air blast circuit breaker



July 28, 1970 J. GOLOTA 3,522,400

ANNULAR SLIDING VALVE FOR AIR BLAST CIRCUIT BREAKER Filed Dec. 15, 19663 Sheets-Sheet l l '5; 1, J15. .Z- '40 1 x Q I /d i:

July 28, 1970 J. GOLOTA 3,522,400

ANNULAR SLIDING VALVE FOR AIR BLAST CIRCUIT BREAKER Filed Dec; 15, 19665 sheets-sheet 2 5 M a 4 flfi, M 1 @Z w I m w ZZZZCZZZ ZZZ I as".

ANNULAR'SLIDING VALVE FOR AIR BLAST CIRCUIT BREAKER Filed Dec. 15, 1966J. GOLOTA July 2-8, 1970 3 Sheets-Sheet 5 United States Patent O3,522,400 ANNULAR SLIDING VALVE FOR AIR BLAST CIRCUIT BREAKER JohnGolota, Los Angeles, Calif., assignor, by mesne assignments, to I-T-EImperial Corporation, Philadel: phia, Pa., a corporation of DelawareFiled Dec. 15, 1966, Ser. No. 601,985 Int. Cl. I-Ilh 33/83 US. Cl.200-448 7 Claims ABSTRACT OF THE DISCLOSURE A compressed gas circuitbreaker in which an axially extending movable contact carries a blastvalve slidably mounted thereon. One end of the movable contact engages anozzle opening in a stationary contact and the blast valve mounted onthe end of the movable contact engages a sealing ring on the stationarycontact. The blast valve, when closed, isolates a high-pressure sourcefrom a low-pressure source. When the blast valve slides down on themovable contact, high-pressure air is immediately adjacent the point ofcontact separation between the movable and stationary contacts.

This invention relates to a novel interrupter structure for compressedair circuit breakers, and more specifically relates to an interrupterstructure having few moving parts, and having an annular air blast valveplaced in close proximity to the breaking gap to minimize consumption ofcompressed air and to reduce operating gas pressure to a minimum.

Air blast circuit breakers are well known to the art where a blast valvecontrols high pressure air so that a blast of air is passed throughcooperating contacts when they are operated in order to extinguish theare drawn between the contacts. Such blast valves are commonlypositioned remote from the point at which the contacts separate. Thisrequires suitable channels for leading the pressurized air to thecontact region. These channels cause a pressure drop in the gas pressureat the contact region,

and also cause a delay in the time it takes for the pressurized air toreach the point of contact interruption. The delay produces a consequentdelay in circuit interruption after the operation of the blast valve,and requires that the blast valve be opened some substantial amount oftime prior to the actual separation of the contacts and until the arc isextinguished. Therefore, there is a loss of pressurized air greater thanrequired solely for are interruption. Moreover, relatively high pressuresources are required in order to compensate for the pressure drop in thevarious connecting conduits between the remote blast valve and thecontacts to obtain the necessary pressure in the contact region.

The principle of the present invention is to provide a novel annularblast valve which seats directly around the annular contact area at theregion at which current interruption occurs. Thus, the instant the valveis opened, high pressure gas is applied directly to the arcing areawithout pressure loss and without delay. Consequently, the valve need beopened only long enough for arc extinction purposes to conservepressurized gas; and the pressurizing equipment need not beover-designed to compensate for pressure drops in gas conductingconduits leading from the blast valve to the contact. The latteradvantage has been found to permit the use of pressure supply equipmentof the order of 250 psi. so that commercially available pressurehandling equipment can be used whereas, the use of pressure carryingconduits from blast valve to contacts required the use of higher andnonstandard pressure equipment.

3,522,400 Patented July 28, 1970 In the preferred embodiment of theinvention, nozzletype contacts are used in the interrupter with amovable nozzle-type contact surrounded by a relatively movable annularvalve. A novel pressurizing arrangement is then provided for forcing theannular valve into sealing engagement with the stationary contact whenthe movable contact engages the stationary contact. The annular valvemember is then movable with relation to the movable contact such that inopening the breaker, the annular valve member will initially move awayfrom the stationary contact to open the valve seal, with this motionimmediately followed by the rapid movement of the movable contact, withboth movable contact and movable valve thereafter moving toward adisengaged position in unison. The annular valve member of the inventionoperates as a free piston-type of member, and is proportioned to providea popping action with the same pressures moving both the annular valveand movable contact in sequence. Thus, contact opening speed will not bedependent on the rate of pressure drop beneath the movable contact sothat a small pilot type dump valve can be used in place of the usuallarge supplemental blast valve for controlling blast valve operation andcontact movement.

Accordingly, a primary object of this invention is to provide a novelgas blast circuit interrupter which requires relatively low supply gaspressures.

Yet another object of this invention is to provide a novel gas blastinterrupter structure for high power circuit breakers which places ablast valve in close proximity to the contact break.

A still further object of this invention is to provide a novel blastvalve for gas blast interrupters which conserves high pressure gas.

Yet another object of this invention is to provide a novel gas blastinterrupter structure which is simple in construction and easy tomaintain, and is highly reliable.

These and other objects of this nivention will become apparent from thefollowing description when taken in connection with the drawings, inwhich:

FIG. 1 is a cross-sectional view of the novel interrupter structure ofthe invention in the open position.

FIG. 2 is similar to FIG. 1 and shows the interrupter structure in itsclosed position.

FIG. 3 is a bottom plan view of the stationary contact of FIG. 1.

FIG. 4 is a cross-sectional view of the upper terminal structure for theinterrupter for FIGS. 1 and 2.

FIG. 5 is a cross-sectional view of FIG. 1 taken across lines 5-5 inFIG. 1.

Referring now to the drawings, the interrupter chamber is comprised ofan insulation tube 10 of suitable material which is fitted and sealed inconductive mounting disks 11 and 12 at its upper and lower ends,respectively. Upper disk 11 is then secured to the disk-shapedstationary contact 12a, shown in bottom plan view in FIG. 3. A gasconducting discharge outlet including tube 13 shown in FIG. 4 isconnected atop contact 12a and contains a standard stationary arcingcontact finger 14 surrounded by a cooler honeycomb 15, schematicallyillustrated, which conducts blast gas through openings in terminal plate"16 to the exterior of the interrupter. The bottom disk 12 is thensecured to bottom casting 20.

Bottom casting 20 is secured and sealed on the end of a suitable hollowsupport insulator 21 with a source of high pressure gas, such as air(not shown) connected to the bottom of insulator 21 and thus to centralchamber 22 beneath casting 20. Casting 20 has a channel 23 forconducting this high pressure gas through valve seat 24 formed incasting 20. A valve member 25 carried on rod 26 is then movable betweenvalve seat 24 and valve seat 27 which is suitably fastened to bottomcasting 20, with valve member normally biased toward engagement withvalve seat 27 by the compression spring 28. A suitable operatingmechanism (not shown) is connected to rod 26 from some remote positionand is responsible for movement of valve 25 as will be later described.

Channel 23 then communicates with channel 28a in bottom casting 20. Theupper portion of channel 28a leads into an annular channel surroundinglower conductive member 29 which is secured to casting 20. Conductivemember 29 has a flange 30 thereon and concentrically surrounds a coolerhoneycomb 31 through which are products and gases may pass to the outletchannel 31a in bottom casting 20 to the external atmosphere.

A movable contact rod 32 having an upper contact section 33 and a lowertail section 34 is then provided with the lower section 34 in slidingrelation within member 29 as illustrated. The movable contact rod 32 hasan opening 35 extending therethrough, and is provided with a series ofresilient buffer plates such as plates 36, 37 and 38, the bottom plateof which is received by the top of member 29 when the movable contact 32is in the open position shown in FIG. 1.

A biasing spring 39 contained between flange 30 of fixed member 29 andflange 40 of the movable contact rod 32 then biases the contact rod 32upwardly toward the position of FIG. 2.

Contact rod 32 is in sliding contact engagement with upper conductivecylinder portion of bottom casting 20 by means of a plurality of slidingcontacts 51 which surround the contact rod 32. By way of example, sixsuch sliding contacts 51 can surround rod 32 as illustrated in FIG. 5.Each of contacts 51 is then biased outwardly and into sliding engagementwith member 50 as by suitable compression springs 52.

The exterior surface of contact rod 32 is then provided with a shoulderwhich serves as a stop for annular blast valve member 61 whichtelescopes over the upper end of contact rod 32. A spring 61a isprovided between shoulder 61b on movable contact rod 32 and the interiorof valve 61 which biases valve 61 upwardly with respect to contact rod32. Blast valve member 61 has a lower cylindrical skirt 62 which fitsover member 50 with a gas-tight seal formed between members 61 and 50 bythe O-ring 67. A second seal is formed between member 61 and contact rod32 by the O-ring 68.

Annular valve 61 is then movable from the lower open position of FIG. 1to the valve closed position of FIG. 2 where the outer surface annularvalve 61 seats against O-ring 69 carried in the stationary contact 112a.

It is to be noted that movable contact rod 32 is movable independentlyof valve 61 to the disengaged position (from the position of FIG. 2 tothe position of FIG. 1), and that when the contact 32 engages stationarycontact 12a, it engages on a radially inwardly directed portion 70 ofthe inverted S-shaped engaging surface of stationary contact 12a.

An annular cavity 80 is then provided within skirt 62 which is connectedto channel 28a to permit compressed gas from cavity 22 to fill cavity80. Channel 22 is connected to main annular chamber 81 formed betweenthe interior of tube 10 and the exterior of extension 50 by virtue ofthe spider type construction of casting 20 as illustrated by dottedlines in FIGS. 1 and 2. Note that channel 28a and chamber 81 are incommunication with one another only when valve 25 is in the positionshown in FIGS. 1 and 2, through the common channels 23 and 28. Whenvalve 25 moves down (and seats on valve seat 24), channel 28a andchamber 81 are isolated by valve 25.

The operation of the interrupter of FIGS. 1 and 2 is as follows:

With the circuit interrupter in the closed position of FIG. 2,compressed air is admitted through chamber 22 through conduits 23 and28, the valve 25 being in its upper position where it seats againstvalve seat 27. The pressure from chamber 28 is then applied under flange40 of movable contact 52 to aid spring 39 in closing contact rod 32, andto the interior volume under valve 61 to aid spring 61a to close thevalve 61, thereby to bias both valve 61 and contact 32 to the engagedposition in FIG. 2. The valve 61 seats on ring 69, thereby to preventcompressed air in chamber 81 from escaping through the center of contact12a or through channel 35in contact rod 32.

In order to open the circuit interrupter, the valve 25 is remotelyactuated through a suitable operating mechanism which is unimportant forpurposes of the present invention, whereby the valve 25 is moved down toseat against valve seat 24. This then vents chamber 28a to the externalatmosphere, thereby permitting the pressure heneath the annular valve 61to fall off rapidly. The valve 61 is so proportioned that the area underthe valve within chamber 80 is less than the area at the top of thevalve exposed to the pressure within the outer chamber 81, therebytending to move the valve toward its lower or open position against theforce of spring 61a. Moreover, when the pressure has fallen sutficientlyto allow the valve to move downwardly and break the seal at gasket 69,the area on top of the valve subject to the higher chamber pressure willnow be equivalent to the full area of the valve including the area whichwas internal of seal 69 which was exposed only to external pressure.This sudden increase in area and resultant multiplication of openingforce will then drive valve 61 rapidly down against shoulder 60 ofmovable contact 32 and independently of movement of movable contact 32.

When the valve 25 vents chamber 28a, pressure under flange 40 of movablecontact rod 32 was also removed. However, the force of spring 39 isstill sufficient to hold contact rod 32 in engagement with stationarycontact 12a. As soon as valve 61 leaves seal 69, however, the entireupper surface of contact 32 is exposed to the high pressure of chamber81 which is sufficient to move contact rod 32 rapidly downward againstthe force of spring 39. That is, in FIG. 2, the surface of valve 61 isdivided into an interior annular region 610 and an exterior annularregion 610', by engagement of gasket 69 and valve 61. When the valveopens, both areas 61c and 61d are exposed to high pressure.

Consequently, in operation, valve 61 is initially unsealed from seal 69whereupon it immediately moves downward independently of contact 32,with a popping type action once the remainder of its internal areawithin seal 69 is exposed. Similarly, the movable contact is exposed tohigh operating pressure immediately after valve 69 is opened whereuponcontact 32 also moves down with a popping action. Since valve 69 opensimmediately prior to separation of contacts 32 and 12a, a strong airblast will be established between the separating contacts to extinguishany are drawn therebetween. This air blast is then conducted through thecooler honeycomb 15 (FIG. 4) to external atmosphere, and through centralopening 35 and through honeycomb 31 to external atmosphere. Note furtherthat there is no delay in applica tion of blast air to the contact afterthe blast valve is opened since this air (and the blast valve) surroundsthe contact area and need not be conducted through auxliiary channels.Thus, air blast need continue only long enough to extinguish the arcwhereby compressed air of the supply is conserved. Moreover, the airpressure at the contacts has the same pressure as the supply source (asmeasured in cavity 22), and it is not necessary to increase the airsupply pressure to account for pressure drops in conduits leading fromthe blast valve to the contact.

In order to shut 011 the blast of air and reset the contacts, theoperating mechanism moving valve 25 is suitably arranged so that thevalve 25 is automatically returned to the position shown in the drawingswhere the valve 25 seats against valve seat 27. This action will permitcompressed air to enter channel 28a and chamber 80, thereby moving thevalve 61 upwardly to seal against O-ring 69 with a snap action. Theclosing of valve 61 removes the pressure from the top of contact 32whereby the pressure beneath flange 40 and spring 39 will move contact32 toward its engaged positon with a subsequent snap action.

Note that a supplemental isolating contact means (not shown) will beconnected in series with the interrupter contacts in the usual manner.This interrupter is synchronized with the operation of valve 25 toestablish an open circuit to prevent the reclosing of contact 32 fromre-establishirrg the circuit which has been opened.

It is to be particularly noted that the air pressure within the movablecontact chamber acts independently on both contact 32. and annular valve61. In this manner, the contact force is made independent of the sealingforce and adds to the force obtained from the main closing spring 39.This results in high contact pressure between contacts 32 and 12a up tothe instant of contact separation. At the same time, the force underannular valve 61 is proportionally lower so as to not develop excessivesealing pressure, thereby allowing the valve to be of light constructionso that it will be rapidly movable under the differential pressuresapplied thereto during opening.

Although this invention has been described with respect to its preferredembodiments, it should be understood that many variations andmodifications will now be obvious to those skilled in the art, and it ispreferred, therefore, that the scope of the invention be limited not bythe specific disclosure herein, but only by the appended claims.

The embodiments of the invention in which an exclusive privilege orproperty is claimed are defined as follows:

1. A gas blast circuit breaker comprising, in combination: a stationarycontact; an elongated movable contact movable bewteen an engaged anddisengaged position with respect to said stationary contact; an annularblast valve of insulation material surrounding the end of said elongatedmovable contact; said annular blast valve having an interior surfaceportion extending along a major portion of the axis thereof; saidinterior surface portion engaging and being axially slidably movable onthe exterior surface of said end of said movable contact and in sealedengagement with said exterior surface of said end of said movablecontact; said annular blast valve having first and second oppositeannular surfaces facing respectively toward and away from said stationrycontact; a first chamber in communication with said second annularsurface of said blast valve; a high pressure gas source; valve means forselectively connecting said first chamber to said high pressure sourceor to a low pressure exhaust region respectively; a second chamberconnected to said high pressure gas source; said movable contact andsaid annular blast valve contained within said second chamber; anopening in said second chamber adjacent the end of said elongatedmovable contact and in the region where said movable contact engagessaid stationary contact; seal ring means disposed in said opening andengageable by an exterior annular region on said first annular surfaceof said annular blast valve; said annular region dividing said firstannular surface into an interior annular portion and an exterior annularportion; said opening in said second chamber communicating with a lowpressure region; said end of said movable contact exposed to said lowpressure region when said first annular surface of said annular blastvalve engages said seal ring means and said movable contact engages saidstationary contact; connection of said first chamber to said lowpressure region by said valve means permitting the re lease of saidfirst annular surface of said annular blast valve from said seal ringmeans whereby high pressure from said second cramber is connected overthe full surface area of said first annular surface of said blast valveto move said blast valve down along said movable contact and said highpressure source is connected over the end surface of said movablecontact, thereby to move said movable contact down and away from saidstationary contact with the opening of said blast valve permitting ablast of high pressure gas through the region between the separatingmovable and stationary contacts.

2. The device as set forth in claim 1 wherein said stationary contacthas a ring shape coaxial with the axis of said elongated movablecontact; said seal ring means embedded in the interior surfce of saidring shaped stationary contact facing said blast valve.

3. The device as set forth in claim 1 which includes gasket meansbetween the sliding cooperating surfaces of said blast valve and saidend of said movable contact for forming a gas tight seal.

4. The device as set forth in claim 1 which includes first spring biasmeans connected to said blast valve for biasing said blast valve towardits sealed position with respect to said seal ring means and secondspring bias means for biasing said movable contact toward its engagedposition with respect to said stationary contact.

5. The device as set forth in claim 1 wherein the pressure of saidsource of high pressure gas is no greater than 2.50 p.s.i.

6. The device as set forth in claim 1 which includes a stationaryconductive support for said annular valve and movable contact; saidstationary conductive support having an elongated sleeve; said elongatedmovble contact having a lower portion thereof slidably disposed withinsaid sleeve and in sliding electrical contact therewith; said annularvalve having a bottom relatively large diameter skirt slidably disposedabout the upper exterior diameter of said sleeve; and pressure sealmeans between said skirt and sleeve.

7. The device as set forth in claim 1 wherein a lower portion of saidmovable contact is contained in said first chamber whereby gas pressureacting against said lower portion of said movable contact biases saidmovable contact toward engagement with said stationary contact.

References Cited FOREIGN PATENTS 1965 Germany. 7/1936 Germany.

